I will be the first to raise my hand and admit I never thought about accessing immigration records via the US Citizenship & Immigration Services website. I read a post on the Eastman’s Online Genealogy Newsletter site and had a genuine Homer Simpson ‘Doh!’ moment.
A little-known program of the U.S. Citizenship and Immigration Services (USCIS) provides genealogy information that may be difficult or impossible to obtain elsewhere. The records include naturalization files, visa applications, and citizenship tests, and may reveal family secrets and mysteries. In addition to relatives, historians or researchers can also request files.
I highly recommend reading the post, which contains an overview of the database as well as a link to the service online: